Advocates for a global climate change treaty immediately attacked the goal. Several noted that the proposed cut is just 1 percent deeper than what Japan agreed to in 1997, when it hosted a conference in Kyoto that ultimately lent its name to the world's first global climate change deal.

Meanwhile, Japanese leaders today also are expected to discuss their plans in terms of 2005 levels. Using that year as the standard, Japan will make the point that it is slashing 14 percent of emissions by 2020. Also, its leaders will likely point out that the midterm target does not include international offsets or measures to avoid deforestation, which could ultimately provide a boost to the county's goals.

"We had a meeting with the Japanese delegation today to express concern about its low level of ambition," said Alden Meyer, strategy director at the Union of Concerned Scientists.

"As the host country of Kyoto, we told them, they have a responsibility to take a leadership role," he said.

Japan's announcement comes at the midpoint of international negotiations toward a new global climate treaty. U.N. leaders hope to hammer out deal by the end of the year. This week, delegates from 192 countries are meeting in Bonn, Germany, to take a first crack at possible treaty language.

A major missing element thus far has been a clear outline of how far the United States, Japan, Canada, Russia and other major emitters of greenhouse gases plan to scale back.

Comparisons to Kyoto

In the United States, congressional Democrats have proposed emissions reductions of 17 percent below 2005 levels by 2020. What shape the final U.S. bill will take, or if it will be signed into law at all, remains an open question.

The European Union has committed to a 20 percent reduction by 2020, and says it will go to 30 percent if others also make strong cuts.

Japan, meanwhile, has seen its own internal tension over picking a midterm target. The country considered a wide range of options, from allowing a 6 percent rise in emissions compared to 1990 levels to the most ambitious target, a 25 percent cut from the same baseline.

The final goal -- 14 percent below 2005 levels by 2020 -- represents a middle possibility. But Kimiko Hirata of the Japanese environmental group Kiko Network said in Bonn yesterday that the numbers are deceiving.

"You may not think this is too bad, but you need to look at it closely," Hirata said. She argued that Japan's emissions have risen since 1990, and Japan's proposal is equivalent to slashing 7 percent from 1990 levels. Under the Kyoto Protocol, Japan agreed to cut emissions 6 percent below 1990 levels by 2020.

"The fact is, Japan says, 'We won't do more than Kyoto,'" she said.

David Turnbull, a spokesman for the Climate Action Network, warned that Japan's numbers could throw the chances of getting concessions on emissions from developing countries like China into a tailspin.

America still the one to watch, activists say

"We're not happy," Turnbull said. "This is a rich country, an industrialized country that should be taking aggressive action. If you're trying to encourage China or India to take on actions ... if you don't have aggressive action in your own country, I don't see how you're going to bring those developing countries along."

Rep. James Sensenbrenner (R-Wis.), the leading Republican on the House Select Committee on Energy Independence and Global Warming and a critic of the international negotiations, noted that China has demanded emission cuts from developed nations "that are far steeper than those Japan is proposing." China has called for industrialized countries to collectively slash 40 percent of emissions from 1990 levels by 2020.

"Until China is willing to adopt mandatory targets of its own, its aggressive demands of other countries should be ignored," Sensenbrenner said in a statement. He argued that countries need to adopt targets that are "realistic" and warned that overly ambitious goals can stifle economic development that could spur low-carbon technologies.

Japan is one of the world's largest emitters of greenhouse gases but also among the most efficient users of energy. The government has pledged to reduce emissions 60 to 80 percent from 2005 levels by midcentury.

Jake Schmidt, international climate policy director at the Natural Resources Defense Council, called Japan's target "a small but insignificant step, especially given where they started from in Kyoto." But, he argued, the decision may ultimately have little impact on the global talks.

"All eyes are really centrally focused on what the U.S. is going to do," he said.